The purpose of this project is to study the cell surface membrane - how it may change in transformation to malignancy either by spontaneous induction or as induced by SV40 virus; to study the nature of tumor antigens associated with cells transformed by either SV40, chemicals, or spontaneous induction; and the relation of these antigens to gene expression and host immune mechanisms. Research is carried out on: 1) Changes in glycoconjugates, including glycoproteins and sulfated glycosaminoglycans such as heparan sulfate, and their correlation with cell growth properties in tissue culture and in vivo, in the syngeneic and in the nude mouse; 2) controls of expression and methods of purification of SV40 specific T antigens, surface antigens and tumor specific transplantation antigens (TSTA); 3) the relationship between SV40 T, surface and TSTA antigens, and their relationship to SV40 A gene expression; 4) a 56,000 MW SV40 induced but cell DNA encoded protein which is also present in embryonal carcinoma cells and in certain embryo cells; 5) study of "spontaneous" transformation of cells in culture and of the balance between such tumorigenicity and the SV40 TSTA in families of clonal cells with known genealogy.